Lithium secondary battery containing silicon-based or tin-based anode active material

Abstract

Provided is a lithium secondary battery comprising an anode mix including a silicon- or tin-based material as an anode active material, and as a binder, a photo-polymerizable material composed of one or more monomers selected from the group consisting of an epoxy derivative, polyester acrylate and epoxy acrylate, or oligomers or polymers thereof, wherein an anode can be prepared within a short period of time via a simplified manufacturing process by applying the anode mix to a current collector and polymerizing the applied anode mix with light-irradiation, and further, superior charge/discharge cycle characteristics of the battery are provided due to stable maintenance of binding between active materials and between the active material and current collector, regardless of significant volume changes of the anode active material occurring upon charging/discharging the battery.

1. A lithium secondary battery comprising an anode mix including a silicon- or tin-based active material as an anode active material and a photo-polymerizable material as a binder, wherein the anode mix includes the silicon- or tin-based anode active material, and the photo-polymerizable material is composed of one or more monomers selected from the group consisting of an epoxy derivative, polyester acrylate and epoxy acrylate, or oligomers or polymers in the range of about 1 to 50% by weight, based on the total weight of the anode mix, and a catalytic amount of a photoinitiator,
 wherein the silicon or tin-based anode active material is a silicon-carbonaceous material complex (Si—C); and 
 the epoxy derivative is bisphenol A, and the epoxy acrylate is bisphenol A epoxy diacrylate, difunctional bisphenol epoxy acrylate or novolac epoxy acrylate. 
 
     
     
       2. The battery according to  claim 1 , wherein the photo-polymerizable material is diluted with a glycol acrylate compound prior to use thereof, or is used with further addition of a polyol acrylate compound. 
     
     
       3. The battery according to  claim 1 , wherein the photoinitiator is a radical photoinitiator, or a cationic photoinitiator using an onium salt. 
     
     
       4. The battery according to  claim 3 , wherein the radical photoinitiator is selected from the group consisting of dialkoxyacetophenone, benzilketal, hydroxyalkyiphenyl ketone, benzoyl oxime ester and amino ketone. 
     
     
       5. The battery according to  claim 3 , wherein the onium salt is a dialkyliodonium salt or a triarylsulfonium salt. 
     
     
       6. The battery according to  claim 1 , wherein the anode mix further includes one or more additional components selected from the group consisting of a viscosity adjuster, a conductive material and a filler. 
     
     
       7. The battery according to  claim 1 , wherein the anode current collector has a thickness of 3 to 500 μm and fine irregularities formed on the surface thereof.